Gongsun Yuan's Rebellion

Gongsun Yuan's Rebellion (June-September 238) was a failed uprising by the self-proclaimed King of Yan, Gongsun Yuan, against the Kingdom of Cao Wei in Liaoning, northeast China. Gongsun Yuan had been courted by the rival kingdom of Wu, which convinced him to rise in rebellion against Emperor Cao Fang. Gongsun Yuan proclaimed himself King of Yan and took over Liaodong commandery, causing the Wei government to send Sima Yi with 40,000 troops to crush the uprising. Assisted by thousands of Goguryeo troops, the Wei forces besieged Gongsun Yuan's stronghold of Xiangping, which was held by tens of thousands more troops than the Wei army. Gongsun Yuan's attempts to surrender were ignored, and he was executed, while many other members of his clan were massacred; 2,000 former officials under his rule and 7,000 of his soldiers were executed in a systematic purge. The Gongsun clan was eliminated, Wei's rival in the northeast was conquered, and Wei was able to establish contact with the peoples of Manchuria, Korea, and Japan.